"That's about right," he said quietly. "I got all the information that the observatories had on the orbit of the Dark Moon. It is circling the Earth from north to south. It coincided for a short time with our own moon when it first hit; that's what kicked up the big wave and jarred us up. But it swung off and seems to have settled down in its own orbit now.

"Two hundred thousand miles away is what they make it, though I think that is more or less of a guess. I wish we could measure our speed." He looked at the earth-induction speed-indicator. Useless now, it registered zero.

"Well," he added, "we are shooting for the North Star. We will pass close to the Dark Moon's orbit; it should be about over the Pole on this date. And there is one good safe bet, anyhow; there is nothing between here and there to stop us."

He was being weakly facetious, but his efforts met with an enthusiastic response. The tension of the moment, it was plain, had not affected Harkness alone. But it was many hours before the error of his statement was made manifest to all.

An island, faintly luminous, lay ahead. It grew to enormous size as they dashed upon it. Harkness sprang for the controls, but, before he could reach them, they had struck the vast field of pale green light, flashed through it, and left it diminishing in size behind them. Then, other lights, not brilliant, but like phosphorescent bodies, that came and went and flashed by with blinding speed.

* * * * *

Another luminous area rushed at them from ahead. At first it was a speck, then an island, and then a continent in size, and through it moved other brighter lights. This time a slight suggestion of an impact was felt. Here was matter of a form they could not guess. It was Chet who pointed to the glass of their control room. The heavy lights of the lookouts were smeared with sticky fluid that drew together in trickling streams.

"Nothing between us and the Dark Moon?" he asked of Harkness. "And space is an empty void? We Earth-creatures are a conceited lot."

"Meaning?" the girl questioned.

"Meaning that because we live on Earth—walk on solid ground, swim in the water and fly in the air—we deny the existence of life in space. There's the answer written in the blood of some life that was snuffed out as we hit it."

Harkness shook his head doubtfully. "Matter of some sort," he admitted, "and the serpents came from somewhere; but, as for the rest, the idea that the ocean of space is filled with life as our Earth-oceans are—creatures living and moving through unknown fields of force...." He did not finish the denial, but looked with wondering gaze at the myriad points that flashed softly into glowing masses and darted aside before their onward rush.

It was hours later that he checked their flight. Slowly at first he cut off the exhaust from their stern and opened the bow valve. Slowly, for their wild speed must slacken as it had been built up, by slow degrees. The self-adjusting floor swung forward and up. Their deceleration was like the pull of gravity, and now straight ahead seemed down.

More hours, and they were at rest, floating in an ethereal ocean, an ocean teeming with strange life. Each face was pressed close to a lookout port. No one of the three could speak; each was too absorbed in the story his eyes were reading—this story of a strange, new existence where no life should have been.

Animalculae. They came in swarms; cloud masses of them floated past; and swirls of phosphorescent fire marked the presence of larger creatures that moved among them. Large and small, each living creature was invisible until it moved; then came the greenish light, like phosphorescence and yet unlike.

* * * * *

Still Harkness could not force himself to believe the irrefutable evidence. What of astronomy? he asked himself. Why was this matter not visible through telescopes? Why did it not make its presence known through interference? Through refraction of light?... And then he realized the incredible distance within the scope of his vision; he knew that this swarming life was actually more widely spaced; and the light of a brilliant star shone toward him through the center of a living mass to prove that here was matter that offered no resistance to the passage of light.

A void of nothingness was before his eyes. He saw its black emptiness change to pale green fire that swirled and fled before a large shape. The newcomer swept down like light itself. Softly green like the others, its rounded body was outlined in a huge circle of orange light. Like a cyclopean pod, it was open at one end, and that open end closed and opened and closed again as the creature gulped in uncounted millions of the tiny, luminous dots—every one, as Harkness now knew, a living thing.

Strange light whirled into life and vanished, each evidencing a battle where life took life in this ocean of the invisible living. A gasp from the girl brought Harkness quickly about.

"Another one!" she said breathlessly, and pointed where the blackness was looped with writhing fire. It came swiftly near to show the outline of the dread serpent form; the suction cups showed plainly.

Danger was in this thing, Harkness knew, but it passed them by before he could move. The further lookout showed two gleaming monsters locked together in deadly embrace. So swift was their whirling motion that details of form were lost: only a confusion of lashing tentacles that whipped and tore, and one glimpse of a savage maw that sheared the tentacles off. Then the serpent was upon them.

* * * * *

Harkness had seen one time a sight that was indelibly impressed upon his memory. A steeloid cable had broken under a terrific strain; the end of it had lashed out with a speed the eye could not follow, to wind itself around the superstructure of a submarine—and the men who were gathered there.

He thought of that now, saw again the bleeding mass that had been an instant before a group of humans, as the serpent seized its prey. The two combatants were encircled in a living coil of light. Then, as motion ceased, the ethereal sea went dark except for pulsing suction cups that drew and strained at the bodies they held.

Harkness was groping for the controls—he saw too plainly their own helplessness when they were at rest—but the voice of Dianne checked him.

"That bright star went out," she said; and Harkness let his gaze follow where she pointed.

The stars that were distant suns shone in brilliant points of light; no atmosphere here to dim them or cause a flickering. A bright point vanished as she looked—another!—and he knew abruptly that he was seeing a circle of blackness that moved slowly between them and the stars.

"The Moon!" he shouted. "The Dark Moon!" And now his hand found the controls that threw their ship into thunderous life. It was approaching! He swung the metal ball to throw them ahead and to one side, and the roar from the stern told of the fast-growing speed that was pressing them to the floor....

* * * * *

An hour of wild flight, and the circle was close upon them. Too faintly lighted to register in the telescopes of Earth, there was still enough of luminosity to mark it as a round disc of violet that grew dimly bluish-green around the edge.

It ceased to grow. Their ship, Harkness knew, was speeding beside it some hundreds of miles away. But they were within its gravitational pull, and were falling toward it. And he aimed his ship bow-on to make the forward blast a check upon their falling speed.

The circle broadened; became a sphere; and then they were plunging through clouds more tenuous than any vapors of Earth—thick layers of gas that reflected no rays from the distant sun.

Beside them a sinuous form showed where a serpent of space was trying to match their speed. Harkness saw it twisting convulsively in the stratum of gas; it was falling, lifeless, beside them as they sped on and away. Here was something the beasts could not combat. He made a mental note of the fact, but his thoughts flashed again to what lay ahead.

Every eye was held close to the lookouts that faced forward. The three were breathless, wordless; the hand of Harkness that held the tiny ball was all that moved.

Ahead of them was their goal, the Dark Moon! And they were prepared for Stygian darkness and a land of perpetual night. The almost invisible gas-clouds thinned; there was a glow ahead that grew brilliant as they watched; and then, with a blinding suddenness that made them shield their eyes, there flashed before them a world of light.

Each line of shore was marked distinctly there; the blue and violet of rippling seas were blended with unreal hues; there were mountains upthrust and, on the horizon, a range of volcanic peaks that poured forth flashing eruptions half-blanketed by invisible gas.

"The Dark Moon!" gasped Harkness. He was spellbound with utter awe at the spectacle he beheld. This brilliant world a-gleam to its farthest horizon with golden, glorious sunlight, softly spread and diffused! This, this! was the Dark Moon!

* * * * *

He turned to share with the others the delirium of ecstatic wonder too overpowering to be borne alone—turned, to find his happiness shot through with a pang of regret. He saw Chet and Diane. They had been standing together at a wide forward lookout; and now she was holding one hand of the pilot to her breast in an embrace of passionate joy.

Unconscious, that gesture of delight at this climax of their perilous trip?—Harkness told himself that this was so. But he swung back to the helm of the ship. He glanced at instruments that again were registering; he saw the air-pressure indicator that told of oxygen and an atmosphere where men might live. He gauged his distance carefully, and prepared to land.

The moment of depression could not last, for there was too much here to fill brain and eyes. What would they find? Was there life? His question was answered by an awkward body that flapped from beneath them on clumsy wings. He glimpsed a sinuous neck, a head that was all mouth and flabby pouch, and the mouth opened ludicrously in what was doubtless a cry of alarm.

Then land, that took form and detail; a mountain whose curled top was like a frozen wave of stone. In a valley below it trees were growing. They swayed in a wind, and their branches reached upward and flowed and waved like seaweed on the ocean's floor. Green—vivid, glowing green!—and reds and purples that might be flowers and fruit.

* * * * *

An open space in a little valley spread invitingly before him, and he laid the ship down there in a jungle of lush grasses—set it down as gently as if he were landing from a jaunt of a thousand miles instead of two hundred times that distance straight away from Earth.

The others were looking at him with glowing, excited eyes. In the cabin was silence. Harkness felt that he must speak, must say something worthy of the moment—something to express in slight degree the upwelling emotion that filled them all, three adventurers about to set foot upon a virgin world....

The pause was long-drawn, until he ended it in a voice that had all the solemn importance of a head-steward's announcement on a liner of the high-level service. But the corners of his lips were twitching to a little smile.

"This," he announced, "is as far as we go. This is the end of our run."

The tension that had held them emotionally taut was ended. With outstretched hands Diane ran toward him, and her broken laugh betrayed the hysteria she was holding back.

"Congratulations!" she cried, and clung tightly to his hands. "Congratulations, M'sieu Walter—"

Her voice choked and she could not go on; but the eyes that were raised to his were luminous through the tears that filled them.

From the cabin beyond came a clash of levers, where Chet was preparing to open a port. And Harkness followed with unseeing eyes where the pilot waited that their commander might be the first to step forth upon an unknown globe—upon the surface of what men had called "The Dark Moon."

CHAPTER VI

Trapped

Walter Harkness, piloting his ship to a slow, safe landing on a new world, had watched his instruments with care. He had seen the outer pressure build up to that of the air of Earth; the spectro-analyzer had shown nitrogen preponderating, with sufficient oxygen to support life. And, below him, a monstrous thing that flopped hurriedly away on leather wings had told him that life was there.

But what would that life be? This was the question uppermost in the minds of all three as they stepped forth—the first of Earth's people to ask the question and to find the answer.

Chet had gone to their stores. He strapped a belt about his waist, a belt banded with a row of detonite cartridges, and a pistol hung at his hip. He handed another to Harkness. But the pistol he offered Diane was refused.

"My many accomplishments," she laughed, "do not include that. I never could shoot—and besides I will not need to with both of you here." Her hand was resting confidently upon Chet's arm as they followed where Harkness led.

The heavy grass, standing waist-high in the little valley where their ship was at rest, stirred to ripples of vivid green as a light breeze touched it. Above, the sun shone warm upon this world of tropical growth. Harkness, listening in the utter silence for sounds that might mean danger, let his eyes follow up the rugged wall of rock that hemmed them in on two sides. It gleamed with metallic hues in the midday glare. He looked on to the sun above.

"A dark moon!" he said wonderingly. "Dark!—and yet it is blazing bright. Why can't we see it from Earth? Why is it dark?... I've an idea that the gas we came through is the answer. There is metal, we know, that conducts an electric current in only one direction: why not a gas that will do the same with light?"

* * * * *

The pilot was listening, but Diane seemed uninterested in scientific speculations. "The trees!" she breathed in rapture; "the marvelous, beautiful trees!"

She was gazing toward distant towering growths where the valley widened. Like no trees of Earth, these monsters towered high in air, their black trunks branching to end in tendrils that raised high above them. And the tendrils were a waving, ever-moving sea of color, where rainbow iridescence was stabbed through with the flash of crimson buds. A down-draft of air brought a heady, intoxicating odor.

And still there was silence. To Walter Harkness, standing motionless and alert amidst the waving grass, it seemed a hush of waiting. A prickle of apprehension passed over his skin. He glanced about, his pistol ready in his hand, looked back for a moment at the ship, then smiled inwardly in self-derision of his fear as he strode forward.

"Let's have a look at things," he said with a heartiness not entirely sincere. "We'll discover nothing standing here."

But the silence weighed upon them all as they pressed on. No exclamations of amazement from them now, no speculations of what might lie ahead. Only wide-eyed alertness and a constant listening, listening—until the silence was broken by a scream.

A man it seemed at first, when Harkness saw the figure leap outward from the cliff. A second one followed. They landed on all fours upon a rock that jutted outward toward the trees.

The impact would have killed a human, but these creatures stood upright to face the concealment from which they had sprung. One was covered with matted, brown hair. Its arms were long, and its fists pounded upon a barrel-like chest, while it growled hoarsely. The other ape-thing, naked and hairless, did the same. They were both uttering those sounds, that at times seemed almost like grunted words, when the end came.

A swishing of leather wings!—a swooping, darting rush of a huge body!—and one of the ape-men, as Harkness had mentally termed them, was struggling in the clutch of talons that gripped him fast.

The giant bat-shape that had seized him reached for the other, too. A talon ripped at the naked face, but the ape-man dodged and vanished among the rocks.

* * * * *

With pounding wings, the bat swept off in lumbering flight, but with its burden it seemed heavy, and failed to rise. The trees were close, and their waving tentacles drew back, then shot out to splash about the intruder. The talons released their hold, and the huge leather wings flapped frantically; but too late. Both captor and captive were wrapped in an embrace of iridescent arms and held struggling in mid-air, while the unmoving watchers below stood in horror before this drama of life and death.

Then a red bud opened. It was enormous, and its flowery beauty made more revolting the spectacle of the living food that was thrust within its maw.

The bud closed. Its petals were like lips.... And Diane, in white-faced horror, was clinging to the protecting arm of Chet Bullard beside her. Chet, too, had paled beneath his tan. But Walter Harkness, though white of face, was staring not at the crimson bud, shut tightly about its living food, but upward toward the broken, rocky face of the cliff.

The flying thing, the unnamed horror of the air, had come silently from on high. None of them had seen it until it struck, and he was sure that the ape-men had been taken unaware. Then what had frightened them? What other horror had driven them in screaming terror to that fearful spring out into the open where they must have known danger awaited?

Did a rock move? he wondered. Was the splotch of color—that mottling of crimson and copper and gray—a part of the metallic mass? He rubbed his smarting eyes—and when he looked again the color was gone. But he had a conviction that eyes, sinister and deadly, had been staring into his, that a living mass had withdrawn softly into a shadowed cave, and that the menace that had threatened the ape-men was directed now toward them.

Was this the reason for the silence? Was this valley, so peaceful in its sunlit stillness, a place of death, from which all living things kept clear? Had the ape-men been drawn there through curiosity at seeing their ship float down?

And the quiet beauty of the valley—it might be as horrible a mockery as the blazing splendor of those things ahead—those beautiful and horrible eaters of flesh! His voice was unsteady as he turned toward the others.

"Let's call this off," he said: "there is something up there. We'll go back to the ship and get up in the air again. We'll find a healthier place to land."

* * * * *

Like Harkness, Chet Bullard held his pistol ready in his hand. "Something else?" he inquired. "You saw something?" And Harkness nodded grimly.

They retraced their steps. A half-mile, perhaps. It had seemed long as they ventured forth, and was no shorter now. And the gleaming, silvery shape of the ship was entirely lovely to their eyes as they approached.

Harkness circled the blunt bow with its open exhaust high above his head. On the far side was the port where they had emerged; its open door would be welcome in its promise of safe seclusion. His sigh of relief was echoed by the two who followed, for the horror and apprehension had been felt by all. But the breath choked abruptly in his throat.

Before them was the door, its thick metal wide-swung as they had left it. But the doorway itself, where warm darkness should have invited, was entirely sealed by a web of translucent stuff.

Harkness approached to look more closely. The substance was glistening and smooth—yellowish—almost transparent. It was made up of a tangle of woven cords which clung tightly to the metal sides. Harkness reached out in sudden fury to grip it and tear it loose. He grasped the slippery stuff, stumbled—and hung suspended by a tenacious hold that gripped his hand where it had touched, and would not let go.

His arm swung against it, and his shoulder. They were instantly immovable. And he knew in a single terrifying instant his utter helplessness. He saw Chet Bullard's hands come up, and he found his voice in time to scream a harsh warning to him.

"Tear me loose!" he commanded, "but don't touch the damned stuff!" It took the combined strength of the pilot and the girl to free him, and Harkness had to set his teeth to restrain an exclamation of pain as his hand came slowly from the web that clung and clung and would not let go.

* * * * *

From his place upon the ground he saw Chet raise a broken piece of rock. It was like metal, and heavy, as the pilot's efforts proved, though it was surprisingly small in size. He saw Chet raise it above his head and crash it upon the thick web that filled the door. And, as his own aching arm had been held, the rock was seized in the tough strands, which gave back only slightly under the blow.

Harkness scrambled to his feet. The fury that had possessed him made the hurt of his arm unfelt. What devil's work was this that barred them from the safety of the ship? The memory of that other menace, half-seen among the rocks, was strong upon him.

"Stand back!" he shouted to Chet and the girl, and he raised his pistol to send a charge of detonite into the unyielding mass. Here was power to tear the clinging-stuff to atoms.

He felt Chet's body plunge upon him an instant before he fired, and his pistol was knocked up and flew outward from his hand. He heard the pilot's voice.

"Walt!" Chet was saying. "For God's sake come out of it! Are you crazy? You might have wrecked that door-port so we never could have fixed it; or the bullet could have gone on through to explode inside the ship. Either way we would never get back: no leaky hull would ever let us make the trip home!"

Chet was right: Harkness knew it in a moment. He knew the folly of what he would have done, yet knew, too, that desperate measures were needed and needed quickly. The eyes of a devil had held his own from the darkness of the rocks, and the same rock wall came close to where they stood. He was in command; it was up to him—

* * * * *

The moment of indecision ended as a mass of viscous fluid splashed heavily against the ship. Harkness whirled about to face the rocks. He was calm now and controlled, but under his quiet courage was a fear that gripped him. A fear of what he should find! But the reality was so far beyond any imagined terror as to leave him cold.

Above them and thirty feet away on a rocky ledge was a thing of horror. Basilisk eyes in a hairy head; gray, stringy hairs; and the fearful head ended in narrow, outthrust jaws, where more of the gray hairs hung like moss from lips that writhed and curled and sucked at the air with a whistling shrillness. Those jaws could crush a man to pulp. And the head seemed huge until the body behind it came into view.

The suddenness with which the great body rose showed the strength of the beast. A prodigious sack, like black leather, with markings of crimson and copper!—and the straggling, ropy hairs on it were greenish-gray like the lustre of the rocks at its back.

It stood upright on great hairy legs. The eyes shot forward on protruding antennae. The sack-like body flexed to bring the rear part under and forward. It was aiming at them.

Harkness seized the slim figure of the girl who stood, mute with horror, beside him. He threw her roughly to the ground, for the meaning of the viscous splash was plain.

"Down!" he shouted to Chet. "Down on the ground!" And he felt the swish of another liquid mass above his head as he obeyed his own command.

He felt for his pistol, then remembered it was gone—lost when Chet sprang upon him. But Chet had his.

"Shoot!" he ordered. "Shoot the damned thing, Chet! Kill the spider!"

Spider! He had named it unconsciously. But the name was inadequate, for here was a thing of horror beyond even a spider of prodigious size. This peaceful valley!—and here was its ruler, frightful, incredibly loathsome!

* * * * *

He waited for the sound of a shot. A cursing, instead, was the only reply: Chet was not firing! Harkness whirled to see the pilot pinned by one arm to the web.

The fluid had caught him; he had not dropped quickly enough. And his right hand that had been raised, and the pistol it held, were clamped fast to the awful stuff.

There was no word of appeal, no call for help, yet Chet Bullard must have known what this meant. But neither did Harkness wait for that word. One spring, and he had the pilot by the waist, and he felt the weight of the girl's slim body added to his as her arms went about him to help. Chet's face went chalk-white as the hand tore loose. The pistol remained buried in the clinging stuff.

From the corner of his eye, Harkness saw the monster crouched to spring. He was half dragging the other two as he stooped and ran for the bow of the ship. The monstrous body thudded against the metal hull behind them.

The leap was prodigious. He saw the sack-like body fall inert, the great, hairy legs shaking. For the moment, the attacker was helpless: but the respite was brief, as the glaring eyes plainly told.

Below the ledge where the beast had been was an opening in the rocks—a bit of black shadow that was darker than the lustrous metal of the cliff. There was a chance—

"I can make it," Chet was saying, as Harkness dragged him on; "help Diane!" But the girl had sprung before them to gain a foothold and extend a helping hand. And they were back in the darkness of a rocky cave before the sunlit entrance was blocked by a hairy head and a horrible, slavering mouth on a body too huge to enter.

CHAPTER VII

In the Labyrinth

Spent and shaken, the three passed onward into the cave. Harkness searched his pockets for his neolite flash; found it—a tiny pencil with a tip of glass—and the darkness of the inner cave was flooded with light.

A box of food tablets was in a pocket of Chet's jacket, and there was water that trickled in a tiny stream out of the rocks. It could have been worse, Diane pointed out with forced gaiety. But Harkness, who had gone back for a final look at the entrance to the cave, found it difficult to smile.

He had found the entrance an opening no longer: it was sealed with a giant web of ropy strands—a network, welded together to a glutinous mesh. They were sealed in as effectively as if the opening were closed by a thick door of steel.

They gathered fungus that grew in thready clumps on the walls, and this served as a mattress to soften the rocky floor that must be their bed. And Harkness sat silent in the darkness long after the others were asleep—sat alone on guard, to think and to reach, at last, a conclusion.

A cleavage in the rocks made a narrow crack to the outside world, and through it the starlight filtered dimly. The thread of light grew brilliantly golden—moonlight, a hundredfold more bright than moonlight on Earth. And he realized that the source of light was their own globe, Earth, shining far through space!

It lighted the cave with a mellow glow. It shone upon the closed eyes of the sleeping girl, and touched lightly upon the rounded softness of a lovely face beneath a tangle of brown curls. Harkness stared long and soberly at the picture she made, and he thought of many things.

No parasite upon society was this girl. He had known such; but her ready wit, her keen grasp of affairs, had been evident in their talks on the journey they had made. They had stamped her as one who was able to share in the work and responsibilities of a world where men and women worked together. Yet there was nothing of the hardness that so many women showed. And now she was altogether feminine, and entirely lovely.

* * * * *

Not far away, Chet Bullard was sleeping heavily. His hand, injured painfully when they tore it from the clinging mass, had been bandaged by Diane. It troubled him now, and he flung one arm outward. His hand touched that of the girl, and Harkness saw the instant quiet that came upon him at the touch. And Diane—her lips were smiling in her sleep.

They had been much together, those two; theirs had been a ready, laughing comradeship. It had troubled Harkness, but now he put all thought of self aside.

"This trip," he thought, "can end only in disaster—if it has not already done so. What a fool I was to bring these two!" And: "If I want to risk my own life," he told himself bitterly, "that's my own affair. But for Chet, and Diane, with their lives ahead of them—" His determination was quickly reached.

He would go back. Somehow, some way, he would get them to the ship. They would return to Earth. And then.... His plans were vague. But he knew he could interest capital; he knew that this new world, that was one great mine of raw metals, would not go long unworked. The metallic colorations in rock walls and mountains had fairly shouted of rich ores and untold wealth.

Yes, they would go back, but he would return. He would put from his mind all thought of this girl; he would forget forever those nebulous plans that had filled him with hope for a happiness beyond all hoping. And he would come back here prepared for conquest.

He put aside all speculation as to what other horrible forms of life the little world might hold: he would be prepared to deal with them. But he still wondered if there were people. He had hoped to find some human life.

And this hope, too, left him; his sense of this globe as an undeveloped world was strong upon him. The monsters; the tropical, terrible vegetation; the very air itself—all breathed of a world that was young. There had not been time for the long periods of evolution through which humanity came.

He tried to tell himself of the wealth that would be his; tried to feel the excitement that should follow upon such plans. But he could only feel a sense of loss, of something precious that was gone. Diane—named for the moon: she seemed more precious now to the lonely man than all else on moon or Earth. She could never be his; she never had been. It was Chet upon whom the gods and Diane had smiled. And Chet deserved it.

Only in this last conviction did he find some measure of consolation during the long night.

* * * * *

"We will rip the big web out with detonite," Harkness told the others when morning came. "But I want to get the spider, too."

A touch upon the web with a stick brought an instant response. Again they saw in all its repulsiveness the thing that seemed a creature of some horrible dream. The eyes glared, while hairy feelers seized the web and shook it in furious rage. Harkness, fearing another discharge of the nauseating, viscous liquid, withdrew with the others far back in the cave.

"Wait," he told them. "I have a plan."

The creature vanished, and Harkness went cautiously forward to the web. He took a detonite cartridge from his belt and placed it on the floor close to the ropy strands. Another, and another, until he had a close-packed circle of the deadly things. Then he placed a heavy, metallic piece of rock beside them and proceeded, with infinite care, to build a tower.

One irregular block upon another: it was like a child at play with his toys. Only now the play was filled with deadly menace. The stones swayed, then held in precarious, leaning uncertainty; the topmost was directly above the cartridges on the floor.

"Back!" he ordered the others, "and lie flat on the floor. I must guess at the amount of explosive for the job."

Chet and Diane were safe as Harkness weighed a fragment of metal in his hand. One throw—and he must not hit the tower he had built.... The rock struck into the network of cords; he saw it clinging where it struck, and saw the web shaking with the blow.

Over his shoulder, as he ran, he glimpsed the onrush of the beast. Again the eyes were glaring, again the feelers were shaking furiously at the web. They touched the leaning stones!

He had reached the place where Chet and Diane lay and saw the beginning of the tower's fall; and in the split second of its falling he threw himself across the body of the prostrate girl to shield her from flying fragments of stone. A blast of air tore at him; his ears were numbed with the thunder of the blast—a thunder that ended with a crashing of stone on stone....

* * * * *

Slowly he recovered his breath; then raised himself to his feet to look toward the entrance. It would be open now, the way cleared. But, instead of sunlight, he saw utter dark. Where the mouth of the cave had been was blackness—and nothing else!

He fumbled for his flash, and stood in despairing silence before what the light disclosed.

The rock was black and shining about the mouth of the cavern. It had split like glass. In shattered fragments it filled the forward part of the cave. The whole roof must have fallen, and a crashing slide above had covered all.

Chet was beside him; Harkness dared not look toward the girl coming expectantly forward.

"We'll use more of the same," Chet suggested: "we will blast our way out."

"And bring down more rock with each charge," Harkness told him tonelessly. "This means we are—"

Diane had overheard. Harkness' pause had come too late.

"Yes?" she encouraged. "This means we are entombed?—buried here? Is that it?"

Her voice was quiet; her eyes, in the light of the little flash, were steady in their look upon the man who was leader of the expedition. Diane Vernier might shudder with horror before some obscene beast—she would tremble with delight, too, at sight of some sudden beauty—but she was not one to give way to hysteria when a situation must be faced. No despair could be long-lived under the spell of those eyes, brave and encouraging.

"No," said Walter Harkness: "we will find some way to escape. This is blocked. We will follow the cave back and see where it leads. There must be other outlets. We're not quitting now." He smiled with a cheerful confidence that gave no hint of being assumed, and he led the way with a firm step.

* * * * *

Diane followed as usual, close to Chet. But her eyes were upon their leader; they would have repaid him for a backward look.

To a mineralogist this tunnel that nature had pierced through the rock would have been an endless delight, but to a man seeking escape from his living tomb it brought no such ecstasy. The steady, appraising glance of Harkness was everywhere—darting ahead, examining the walls, seeking some indication, some familiar geological structure, that might be of help.

He stopped once to kick contemptuously at a vein of quartz. Three feet in thickness—and it crumbled to fragments under his foot to release a network of gold.

"Rotten with it," he said.

And the only comment came from Chet: "A fat lot of good it does us!" he replied.

The cavern branched and branched again; it opened to a great room higher than their light could reach; it narrowed to leave apertures through which they crawled like moles; it became a labyrinth of passages from which there seemed no escape. Each turn, each new opening, large or small—it was always the same: Harkness praying inaudibly for a glimpse of light that would mean day; and, instead—darkness!—and their own pencil of light so feeble against the gloom ahead....

CHAPTER VIII

The Half-Men

"The Valley of the Fires," Harkness was to call it later, and shorten it again to "Fire Valley." The misty smokes of a thousand fires rose skyward from the lava beds of its upper end.

Where the lava flow had stopped and the lower valley began, came vegetation. Sparse at first, then springing to luxuriant growth, it contrasted strongly with the barren wall beside it and the equally barren waste of high ground where the fires were.

Mountains hemmed it in; their distant peaks showed black, with red and green striations of mineralized deposits. The valleys about them were dense with foliage, a green so startling and vivid as almost to offend the eye.

Trees were in the lower end of the valley. They were of tremendous growth, and the dew of early morning dripped from them like rain. Trunks smooth and ghostly white, except where the bark had split into countless fractures and the scarlet color of the sap-wood showed through. Outflung branches forked to drop down dangling stalks that rooted again in the ground; these made a forest of slender white supports for the leafy roof—a forest of spectral shapes in a shadow-world. Only here and there were arrows of sunlight that pierced the dense foliage above to strike through and down to the black earth floor and the carpet of rainbow hues.

And that carpet of radiant colors was trampled into paths that wound on to lose themselves in the half-light of that ghostly world.

* * * * *

From one of the paths came sounds of tramping feet. Cries and snarling grunts resounded through the silence to send lizards scurrying to the safety of the trees. Animal cries or hoarse voices of men—it would have been difficult to tell which. And a sight of the creatures themselves would have left an observer still in doubt.

A score of them, and they walked upright. Some bodies were naked, a coppery-black in color; on others the skin was covered by a sparse growth of hair. Noses that were mere nostril-slits; low foreheads, retreating flatly to a tangle of matted hair; protruding jaws which showed the white flash of canine teeth as the ape-like faces twisted and the creatures tugged at ropes of vines thrown over their shoulders.

The Neanderthal Man had not learned to use the wheel; and these man-animals, too, used only the sheer strength of their corded muscles as they hauled at the body of a beast.

It dragged along the path behind them, rolling at times to show the white of its belly instead of the flexible armor-plating that protected its back. Fresh blood flowed from a wound in the white under-skin; this, and the dripping flints that tipped their spears, told how death had come. One curving horn that projected from a wrinkled snout caught at times in the undergrowth, and then the ones who dragged it would throw themselves upon the head with snarls of fury and twist the big horn free.

The rocky cliff was honeycombed with caves. A cry, half-human in its tone, brought an avalanche of figures scurrying forth. Children, whose distended abdomens told of the alternate feasting and hunger that was theirs, were cuffed aside by women who shouted shrilly at sight of the prize. Older men came, too, and in a screaming mob they threw themselves upon the carcass of the beast that had been dragged into the open.

* * * * *

Flint knives came into play, then sharpened stakes that were thrust through the bleeding meat. Young and old seized what they could, leaped across the little stream that trickled downward through the valley, and raced for the nearest fires.

The fumaroles made places for roasting, and these half-men had learned the taste of cooked meats. Their jaws were slavering as they waited. The scents were tantalizing.

A hunter was reaching to snatch a shred of half-cooked meat when a woman of the tribe gave a scream that was shrill with fear. She pointed her gnarled hand upward on the face of the cliff.

An opening was there, a black cave-mouth in the black cliff. Above their own caves, was this higher opening, yet they must have explored it often—must have followed it as far as they dared, where it led to the mountain's innermost depths. Yet from this familiar place there stepped forth an apparition. Another followed, and another—three strange creatures like none the savage eyes of this world had ever seen.

Clothing torn to rags—faces black and smeared with blood—hands that reached groping and trembling toward the light, until the half-blinded eyes of one saw the trickling brook.

Then, "Water!" he croaked in a voice hardly more human than the grunts of horror from below, and he took the hand of another to help in the steep descent—while the tribe beneath them forgot their anticipated feast, forgot all but their primordial fear of the unknown, and, with startled cries, broke and ran for the safety of the forest....

CHAPTER IX

The Throwers of Thunder

It is doubtful if Walter Harkness heard or consciously saw that fleeing tribe. He saw only the glorious sunlight and its sparkling reflection upon the stream; and in his nostrils was the scent of roasting meat to rouse him to a frenzy.

For seven Earth days he and Chet had kept account of the hours. How long after that they had followed their stumbling course he could not have told. Time ceased to be measured in hours and days; rather was it reckoned in painful progress a foot at a time up rocky burrows, helping, both of them, to ease the path for the girl who struggled so bravely with them, until aching muscles refused to bear them further. Then periods of drugged sleep with utter fatigue for an opiate—and on again in hopeless, aimless wandering.

And now, the sun! And he was plunging his head into icy water to drink until he strangled for breath! He knew that Chet and Diane were beside him. A weak laugh came to his lips as he sat erect: the girl had drunk as deeply as the rest—and now she was washing her hands and face.

The idea seemed tremendously amusing—or was it that the simple rite indicated more than he could bear to know? It meant that they were safe; they had escaped; and again a trifle like cleanliness was important in a woman's eyes. He rocked with meaningless laughter—until again a puff of wind brought distinctly the odor of cooking food.

A hundred feet away, up higher in the valley, were the first of the fires. Harkness came to his feet and ran—ran staggeringly, it is true, but he ran—and he tore at some hanging shreds of smoking meat regardless of the burn. But the fierce gnawing at his stomach did not force him to wolf the food. He carried it back, a double handful of half-cooked meat, to the others. And he doled it out sparingly to them and to himself.

The cold water had restored his sanity. "Easy," he advised them; "too much at first and we're done for."

* * * * *

He was chewing on the last shred when a thought struck him; he had been too stunned before to reason. For the first time he jerked up his head in startled alarm. He looked carefully about—at the meat on its pointed stakes, at the distant fires, at the open glade below them and the dense jungle beyond where nothing stirred.

"Cooked meat!" he exclaimed in a whisper. "Who did it? This means people!"

The memory that had registered only in some corner of a mind deeper than the conscious, came to the surface. "I remember," he said. "There were things that ran—men—apes—what were they?"

"Oh, Lord!" Chet groaned. "And all I ask is to be left alone!" But he wearily raised himself upright and verified the other's words.

"They ran toward that opening among those trees. And I'll bet they live in these caves up here behind us. I got a whiff of them as we came past: they smelled like a zoo."

They had come out on top of the lava-flow, close to its end. The molten rock had hardened to leave a drop of some forty feet to the open glade below. Beyond that the jungle began, but behind them was the lava bed, frozen in countless corrugations. Harkness rose and helped Diane to her feet: they must force their aching muscles to take up their task again.

He peered up the valley where a thousand fires smoked. "That stream," he said, "comes in from a little valley that branches off up there. We had better follow it—and we had better get going before that gang recovers from its surprise."

They were passing the first of the fires where the meat was smoking when Chet called a halt. "Wait a bit," he begged: "let's take a sirloin steak along—" He was haggling at a chunk of meat with a broken flint when a spear whistled in and crashed upon the rocks.

* * * * *

Harkness saw the thrower. Beyond the lava's edge the jungle could be seen, and from among the spectral trees had darted a wild figure whose hairy arm had snapped the spear into the air.

There were more who followed. They were sliding down the slender trunks that supported the branches and leafy roof high above the ground. To Harkness the open doorway to the jungle seemed swarming with monkey-men. The movement of the three fugitives had been taken as a retreat, and the courage of the cave-dwellers had returned.

Harkness glanced quickly about to size up their situation. To go on was certain death; if these creatures came up to meet them on the lava-beds, the end was sure. The escarpment gave the three some slight advantage of a higher position.

One vain wish for the pistol now resting in the deep grass beside a vanished ship; then he sprang for the weapon that had been thrown—it was better than nothing—and advanced cautiously to the lava's edge.

No concealment there; no broken rocks, other than pieces of flint; a poor fortress, this, that they must defend! And the weapons of their civilization were denied them.

Another spear hummed its shrill song, coming dangerously close. He saw women-figures that came from the jungle with supplies of weapons. Short spears, about six feet long, like the one he held. But they had others, too—long lances of slender wood with tips of flint. Thrusting spears! He had a sickening vision of those jagged stone heads ripping into their bodies while these beasts stood off in safety. It was thus that they killed their prey. And Diane—he could not even spare her—could not give her the kind oblivion of a mercy-shot!

The other two were lying beside him now at the edge of the sloping cliff. The bank of shining gray was not steep; the enemy would climb it with ease. Hopeless! They had won through for this!... Harkness groaned silently in an agony of spirit at thought of the girl.

"Oh, for one detonite shell to land among them!" he said between clenched teeth—then was breathless with a thought that exploded within his mind.

* * * * *

His fingers were clumsy with haste as he fumbled at the head of the spear. The sharp-edged stone was bound to its shaft with sinew, wound round and round. The enemy were out in the open; he spared an instant's look to see them advancing. A clattering of falling spears sounded beyond, but the weapons were overcast, thanks to the protection of the rocky edge.

"A shell!" Harkness spoke with sharp intensity. "Give me a cartridge from your belt, quick!"

Chet handed him one. Harkness took one look, then pulled a cartridge from his own belt.

"That explains it," he was muttering as he worked, "—the big explosion when I smashed the rocks. You've got ammunition for your pistol, but you put rifle cartridges in my belt—and service ammunition at that. No wonder they raised the devil with those rocks!"

His fingers were working swiftly now to bind the slender cartridge to the spear. A chipped out hollow in the flint made a seat. He gave silent thanks for Chet Bullard's mistake. Chet had slipped; he had filled Harkness' belt with ammunition that would have been useless for the pistol—but it was just what he needed here.

So intent was he on his task that he hardly heard the yelling chorus from below. It swelled to a din; but his work was finished, and he looked up.

One figure in advance of the rest had been urging them on, and they came in a wild rush now. Walt Harkness scrambled to his feet. Tall and sinewy, his broad shoulders, scantily covered by the rags of blouse that remained, were turned sideways as he raised the spear. The yelling from below swelled louder and more shrill.

This strange one from another tribe—he was unarmed except for one of their own spears. The curious covering on his body was flapping in the breeze. Nothing here, surely, to hold a hunting-tribe in check.

The spear rose slowly in the air. What child of the tribe could not have thrown it better! They came on faster now; the leader had almost reached the place where the spear was dropping down. He must have laughed, if laughter had yet been born in such a breast, at the futile weapon dropping point first among the rocks.

One little shell, a scant three inches long, no thicker than the stylus on milady's desk! But here was service ammunition, as Harkness had said; and in the end of the lead a fulminate cap was buried—and a grain of dense, gray dust!

* * * * *

There was no flame—only a concussion that cracked upon one's ears, and flying rock fragments that filled the air with demoniac shrieks. And then that sound was lost in the shriller cries of terror and pain as the ape-men broke for the trees.

Harkness saw some of them who rose and fell again to rise no more, and one who dragged himself slowly from the blast that had struck him down. But his eyes came back to another spear in his hands, and his fingers were tearing at the sinew wrapping.

The spear bent in his hands; the wood was flexible and springy. It was Diane who offered the next suggestion. She, too, was working at another spear—what wonder if her breath came fast!—but her eyes were alight, and her mind was at work.

"Make a bow!" she exclaimed. "A bow and arrow, Walter! We are fighting primitive men, so we can't scorn primitive weapons." She stopped with a little exclamation of pain; the sharp tip of the flint had cut her hand.

Chet's spearhead was unloosed. He tried the spring of the shaft. "Bully girl, Diane!" he said, and fell to gouging out a notch with the sharp flint near the end of the shaft.

The sinew made a string. Three slender sticks lying about whose ends had been sharpened for use on the meat: they would do for arrows. Each arrow must be notched and headed with an explosive shell, and there were many of them.

Chet sprang to his feet at last. Forgotten was the fatigue that had numbed him. A wild figure, his clothes in rags, his short, curling hair no longer blond, his face a mottling of brown and black, where only here and there the white skin dared show through—he executed an intricate dance-step with a bed of lava for a floor, while he shouted:

"Bring on your fighters! Bring 'em on! Who's going to stop us now?"

* * * * *

They were free to go, but Harkness paused at a renewed screaming from the jungle. Again the hairy ones poured forth into the open glade. He had half raised his bow, with arrow ready, before he saw that this was no attack.

The screams merged discordantly with other sounds—a crashing of uprooted trees—a chorus of harsh coughing—snorting—unrecognizable noises. And the people were cowering in terror.

They half-ran toward the safety of their caves, but the throwers of thunder, the demons on the lava bed, were between them and their homes. They turned to face the jungle, and the wild sounds and crash of splintered wood that drew near.

Harkness saw the first head that appeared. He stared in open-mouthed amazement at the armored monster. Thick plates of shell covered its mammoth body and lapped part way over the head to end at beady, wicked, red eyes on either side of a single curved horn.

An instant the animal waited, to glare at the cowering human forms it had tracked to their lair; others crashed through beside it; and in that instant Harkness recognized the huddled group below as brothers. Far down they were, in the long, weary path that was evolution, and hardly come as yet to a consciousness of self—but there were those who leaped before the others, their long spears couched and ready; they were defending the weaker ones at their backs; they were men!

And Harkness was shouting as he raised his crude bow. "Shoot!" he ordered. "Kill the brutes!" His own arrow was speeding true.

The rush of mammoth beasts was on as he fired, but it was checked as quickly as it began. An inferno of explosions rose about the rushing bodies; crashing detonations struck two of them down, their heads torn and crushed. Between the helpless, primordial men and the charging beasts was a geyser of spouting earth and rocks, through which showed ugly heads and tremendous bodies that wheeled and crashed madly back into the jungle growth.

Harkness suddenly realized that only he and Chet had fired. Diane's bow was on the ground. He saw the girl beside it, sitting upright; but her body was trembling and weaving, and she was plainly maintaining her upright posture only by the greatest effort.

* * * * *

He was beside her in an instant. "What is it?" he demanded. "Are you hurt? What is it?"

She raised her hand that he might see; her lips, seemed almost too numb for speech.

"Only a scratch," she whispered, but Harkness saw her eyes glazing. He dropped to his knees and caught her swaying body in his arms.

"A scratch," she repeated in a fading voice, "from the spear.... Poison ... I think."

A head appeared over the lava crest. Harkness saw it vaguely. He knew that Chet had the newcomer covered; his bow was drawn. It meant nothing to him, for Diane was wounded—dying! Dying, now, in his arms....

The ape-man came on; he was grovelling upon the ground. He was hairless, like the one they had seen escape the attack of the giant bat, and his cheek was slashed with a healing cut that might have been made by a ripping talon. He abased himself before the awful might of these creatures who had saved them. And he made motions with his arms to picture how they had sailed down from the skies; had landed; and he had seen them. He was plainly petitioning for pardon and the favor of these gods—when he dropped his animal head to stare at the girl and the cut hand that Harkness held in his.

The blue discoloration of the wound must have been plain in its significance. The hairless one sprang abruptly to his feet and darted toward a cave. He was back in a moment; and, though be approached with wriggling humility, he reached the girl and he ventured to touch the discolored hand with a sticky paste. He had a gourd that he held to the girl's lips.

Harkness would have struck it away; he was beside himself with grief. But Chet interposed.

"Give it to her," he said in a sharp, strained voice that told of his own dismay. "I think the beggar knows what he's about. He is trying to help."

The lips were lax; only a little of the liquid found its way down her throat. But Harkness, after minutes of agony, saw the first flutter of lids that betokened returning life....

CHAPTER X

"But Awfully Dumb...."

Harkness would never forget the helpless body in his arms, nor the tender look that came slowly to the opened eyes that gazed so steadily into his. And yet it was Chet that she seemed to want for the thousand little services during the week that followed. And Harkness tried to still the hurt in his heart, and he told himself that it was her happiness be wanted more than his; that if she found greater pleasure in having Chet near, then his love was unworthy if it placed itself as a bar to that other happiness.

He talked by signs with the hairless one whom he called Towahg. It was the sound the other made as he struck upon his chest. And he learned that Towahg could guide him to the ship.

The tribe had left them alone. Only Towahg seemed inclined to friendliness; and Harkness frequently saw the one who was their leader in ugly, silent contemplation of them when Towahg brought food and water to their cave.

Diane was recovering, but her progress was slow. She was able at once to walk and go slowly about, but the least exertion tired her. It had been a close call, Harkness knew, and he realized that some time must pass before she could take up the hardships of the trail. And in the meantime much might happen.

He felt that he must reach the ship at the first possible moment and return for the others; Towahg would show him the way. He explained the plan to Chet and Diane only to meet with emphatic dissent.

"You would go alone?" the girl exclaimed. "To meet heaven knows what dangers? No, no, Walter; you must not! Wait; I am stronger; I can go soon, I know."

Chet, too, was for delay—Diane was better, and she would improve steadily. They could carry her, at first. But Harkness looked at the jungle he must penetrate and knew that he was right.

* * * * *

He gave Towahg a bow and arrows like his own and those that Chet kept for defense, but the arrows were of sharpened wood without detonite tips. He grinned toward Chet as he showed the savage how to handle the marvellous thing.

"We've advanced these people a thousand years in the science of arms," he said. "They should make Diane their first Minister of Munitions, or worship her as their own lovely goddess of the chase."

A weapon that would throw farther than the strongest man could cast a spear—here was magic indeed! And Towahg knelt and grovelled on the ground at his benefactor's feet.

Harkness made light of the dangers he must face, but he knew in his own mind he might fail. And the time of leaving found him curiously depressed. He had gripped Chet's hand, then turned to Diane for what might be a last good-by. The quick enfoldment of her soft body in his arms was as unpremeditated as the kiss he placed upon her lips.... He swung away abruptly, and fell in behind his guide without a word. The way led first across the place of smoke and fire.

Danger ahead on this strange trail; he knew it well. But he took it as it came; and his guide, and his crude weapon, and his steady eye and sureness of foot on rocky crags all saw him through. And he mentally mapped the hills and valleys and the outcrops of metals that he would explore some later time. Only seven of the short six-hour days of this little earth had passed when he drew near the ship.

He was ready for an attack. There was the broken rubble that marked the entrance of the cave. Beneath it, he knew, were mangled, horrible remains. This one beast alone, it seemed, had been the ruler of the valley, for no other appeared.

The mass that had blocked the doorway was crystalline now, and broke to brittle fragments at a blow. He entered the familiar cabin of the ship. There was nothing disturbed; the sealed inner door had barred entrance to any inquiring beasts.

Far down the valley he saw a naked, running figure. Towahg had escorted this sky-god to the great bird that had brought him, but the courage of even so advanced a tribesman as he must have limits. He was still running along the path they had come when Harkness closed and sealed the door.

* * * * *

There was an instrument among their stores for taking samples of gas. Harkness attached it to the ship before he left, and he took a few precious minutes for a flight into the heights. That gas up there was fatal to the monsters of space: he must secure a sample and learn its composition.

A closing of the switch on wires that led to the instrument outside, and he knew that the container had emptied its contents of water, drawn in the gas and sealed itself.

Then the swift descent.

He flew low as he circled back. They had traveled far on their journey below ground; it was even a longer route where he and Towahg had circled about. But it was the only route he knew; he could take no chances on a short-cut and a possible long-drawn search for the little valley.

He followed the trail. The quick dusk was near; but in an hour's slow flying, while his eyes searched the hills and hollows, the valley was in sight.

He came down slowly in a black sky, with only the soft, muffled roar of the lower exhausts. It was growing dark, and he leaned from an open door to see more clearly his position. All was different from the air, and he needed time and careful scrutiny to get the bearings of the place.

The soft thunder from below was in his ears when a sound pierced through. His own name! And it was Diane's voice calling him in a terrified tone.

"Walter!" she cried. "Help! Help! Oh, Walter, come quickly!"

* * * * *

The scene below was lighted by fitful fires. He was above the upper valley, a hundred yards from their cave: his mind was oriented in an instant, and he knew each foot of ground.

And here, where neither Diane nor Chet should be, was Diane. He saw her running in the bright glare of his landing light that he now switched on; saw a black shape hurl itself upon her; she was struggling. He threw himself back at the controls to send the ship like a thunderbolt upon the earth.

A pistol was in his hand as he leaped from the still-rocking ship and threw himself upon the thing that ran and tried to carry a struggling burden in its arms.

He could not fire; but he brought the pistol down upon a heavy skull. The hairy figure seemed never to feel the blow. It dropped the body of Diane and turned, and its slavering, shining fangs were set in a horrible face that Harkness recognized.

It was the leader of the tribe, and he had dared to attack. But where was Chet? What of his arrows and their detonite tips? These thoughts were crowding through his mind in the instant that ape-like fingers gripped at his throat—the instant while he was bringing the pistol forward and up.

A light charge of detonite in pistol ammunition—but no living body could withstand the shock. Harkness leaped over the fallen foe to reach the girl. She was half risen to a sitting posture as he came.

"Dieu!" she was whispering; "Ah, le bon Dieu!" Then she cried out: "Walter! Oh, Walter, they have killed Chet! Down there!" Her hand was pointing. She grasped at Harkness' hand to draw herself to her feet and race with him toward the cave.

* * * * *

"Just at dark," she explained gaspingly as they ran. "It was their chief, and there were others with him. They leaped upon Chet—before he could reach for his bow. They had seemed so friendly after you left—but they were short of food—"

Her voice was sobbing now, but she kept on, and she set a pace that Harkness could not outdistance.

"One aimed a spear at me, and Chet threw himself between. I saw the spear strike—then I ran. I thought I heard your motors—I screamed for you—"

They were nearing the caves. A fire was burning in the open glade where grotesque figures leaped and danced in cannibal glee about a figure that lay motionless upon the ground.

The tattered, wind-blown clothing—the curling hair, blond in the fire's light—it was Chet.... And now Harkness could fire.

His pistol held twenty rounds. He emptied it into the shrieking group, then jammed in more of the shells and fired again. He fired until no target remained, and every savage figure was either vanished among the trees or inert and lifeless upon the ground, their only motion the stirring of their hairy coverings in the breeze.

* * * * *

Harkness was beside the prostrate figure. He raised Chet's head within his arms; Diane's brown head leaned close, her gasping breath broken by dry sobs. The firelight flickered upon the closed lids to give them semblance of life.

"Chet," said Walter Harkness softly. "Chet, old man—can't you speak? We'll save you, Chet; you're not done for yet." But he felt as he spoke that the words were a horrible lie; the blood that ran slowly now from a wound in Chet's side seemed to speak more truly than did he.

Yet Chet Bullard opened his eyes. His breath was the merest flutter; the listeners bent their heads close to hear.

"Made it, did you?" asked Chet in a ghastly whisper. "And you've saved Diane?... Good!... Well, it's been a great trip.... It's been worth the price...."

Harkness seized at the girl's name. Here was something that might strike home to the sinking man; might rouse him.

"Yes, Diane is saved," he told Chet: "saved for you, old fellow. You must live—for Diane's sake. You love her, and she needs you."

Again the tired eyes opened. Once more the fluttering breath formed words; lips moved to bring a pale ghost of Chet's ready smile like a passing light across his face.

"Needs me? Diane?" It was a question and a denial. He was looking straight at Harkness as he added: "It's you she needs.... You're one square old sport, Walt, but dumb—awfully dumb...."

* * * * *

Glorious adventure!—and the price is so often death. "A great trip," Chet Bullard had said; "it's been worth the price." Chet was prepared to pay in full.

But—there was the ship! Walt Harkness, as she finished bandaging the body of the unconscious man, stared first at the metal cylinder, gleaming, brilliant in the Earthlight; then his gaze went to the Earth that had risen over distant peaks with the glory of a thousand moons. And he dared to hope.

He brought the ship softly to rest close to where Chet lay, then placed the limp form on the self-adjusting floor of the control room. There must be no shifting of the body as the pull of gravitation ceased. Soft blankets made a resting place for him.

The entrance port was closed and sealed; and the ship rose gently under his touch. And, below them, the mirrors showed a world that sank away. Diane's head was pressed near to his to watch that vanishing world.

Each rugged mountain was softened in the Earthlight's mellow glow; they melted together, and lost all sharpness of form. And the light faded and vanished as they rose into the blanket of gas that blocked off the return rays and made of this world a dark moon.

No regret now for the territory that was unexplored. Harkness told himself he would return. And, with the vanishing of that world his thoughts were only of the little flame of life that still flickered in Chet's body, and of the Earth, and of the metal ball that was swinging them out and away.... The sound of the stern exhaust built up and up to the roaring thunder that meant the blast was opened full....

CHAPTER XI

"Nothing to Be Done"

Unmoving, their ship seemed, through the long hours. Yet there were lights that passed swiftly and unnoticed, and the unending thunder from the stern gave assurance that they were not floating idly in the vast sea of space.

The sun was behind them, and ahead was Earth in midday glory; Harkness could not tear his eyes away from that goal. He stood always at the controls, not because there was work to be done, but for the feeling it gave him of urging the ship onward.

Diane ministered to Chet and dressed the wound. There were few words exchanged between them.

The menace that had emptied Earth's higher levels of all aircraft was still there. No ships were in sight, as Harkness guided his ship toward the great sphere. His speed had been cut down, yet still he outraced the occasional, luminous, writhing forms that threw themselves upon them. Then the repelling area—and he crashed silently through and down, with their forward exhaust roaring madly to hold them in check.

A sea and a shoreline, where a peninsula projected like a giant boot—and he knew it for Italy and the waters of the Mediterranean.

"Vienna," Diane was telling him; "go to Vienna! It is nearby. And I know of a surgeon—one of the greatest!"

And an hour later, a quiet, confident man was telling them: "But yes!—of a certainty he will live. It is fortunate that you were not very far away when the accident occurred." And only then did Harkness catch Diana's eyes in an exchange of glances where unbearable relief was tempered with amusement.

* * * * *

The great hospital had its own landing stages on its broad roof. Their ship was anchored there, an object to excite the curiosity of a gathering throng.

"Not a healthy place for me, here in Vienna," Harkness remarked. He was lifting the ship from its anchorage, its errand of mercy done.

"Now where?" he pondered aloud. The strain of the flight was telling on him.

The girl recognized the strained look in his eyes, the deep lines that their experiences had etched upon his face. Gently she drew his hand from the controls.

"I will take it," she said. "Trust me. Lie down and rest."

Harkness had witnessed an example of her flying skill; she could handle the ship, he knew. And he threw himself upon a cot in the cabin to sink under the weight of overpowering fatigue.

He felt the soft shock of their landing. Diane was calling him, her hand extended to lead him from the open port. But he was wrenched sharply from the lethargy that held him at sight of his surroundings, and the memories they recalled.

They were in a park, and their ship rested upon a spacious lawn. Beyond were trees where a ship had shot crashingly through storm-tossed limbs. And, before him, a chateau, where a window had framed the picture of a girl with outstretched arms.

"Trust me," Diane had said. And he did trust her. But did she not know what this meant? She was delivering him into the enemy's hands. He should have kept himself from sight until he had rallied his forces.... He was stammering words of protest as she led him toward the door. Armed guards were already between him and the ship.

* * * * *

In a dark-panelled room Herr Schwartzmann was waiting. His gasp of amazement as he sprang to his feet reflected the utter astonishment written upon his face, until that look gave place to one of satisfaction.

"Mademoiselle," he exclaimed, "—my dear Mademoiselle Diane! We had given you up for lost. I thought—I thought—"

"Yes," said Diane quietly, "I believe that I can well imagine what you thought."

"Ah!" said Herr Schwartzmann, and the look of satisfaction deepened. "I see that you understand now; you will be with us in this matter. We have plans for this young man's disposal."

The puzzled wonder that had clouded the steady eyes of Walter Harkness was replaced by cold anger and more than a trace of contempt.

"You can forget those plans," he told Schwartzmann. "I have plans of my own."

"Poof!" exclaimed the heavy, bearded man. "We will crush you like that!" He struck one heavy fist upon the desk. "And what will you do?"

"Several things," said Harkness evenly. "I shall rid the upper levels of the monsters: I have a gas that will accomplish that. I shall restore the world's flying to normal. And, with that attended to, I will give you my undivided attention—raise forty kinds of hell with Herr Schwartzmann and the interests he represents.

"Forgery! Theft! The seizing of my properties by virtue of a lying document! You shall see what this leads to. Your companies will be wrecked; not a decent man or woman engaged in the business of a decent world will deal with you: that is a small part of what I plan."

The dark face of Herr Schwartzmann was flushed with anger. "You will never leave this place—" he began. But Harkness would not let him go on: his voice was as hard as the metal of his ship.

"You and your assassins!" he said contemptuously. "You don't dare touch me. There is another man who knows—and Diane, too." He paused to look into the eyes of the girl, which were regarding him with an inscrutable expression. "I do not know why she brought me here, but Diane also knows. You can't throttle us all."

"Diane!" The exclamation was wrung involuntarily from Schwartzmann's lips. "You speak of Mademoiselle Vernier so familiarly?"

* * * * *

The girl's cool voice broke in. She had watched the meeting of the men in silence; she spoke now as one taking matters into her own quite capable hands.

"You may omit the incognito, Herr Schwartzmann," she said; "it is no longer required. I have enjoyed a birthday since last we met: it was passed in a place of darkness and anguish, where strong men and brave forgot their own suffering to try by every means to bring comfort to a girl who was facing death. For that reason I say that I enjoyed it.... And that birthday was my twenty-first. You know what that means."

"But Mademoiselle Vernier—pardon!—Mam'selle Delacoeur, surely you will support me. My trustee-ship during all these successful years—"

"Is at an end," said the cool voice.

"I learned more than you were aware of in this last year while I familiarized myself with the interests that would soon be mine. No, Herr Schwartzmann, your methods do not appeal to me; they are an anachronism in the world of to-day."

Harkness was standing in stunned silence. "Delacoeur!" Diane was Mademoiselle Delacoeur! But that name had been borne by the wealthiest house of France! Old Delacoeur had died, possessed of millions beyond counting—and he had left a daughter—Diane!

His mind could not grasp the full significance of this. But one thing was clear: he could not aspire to the love of one of the queens of Earth. Whatever faint hope that remained in his heart was lost.... The cool voice was still speaking.

"You may leave now," she was saying—this girl who had been his comrade, so unfailingly tender, so true and steady in the face of incredible dangers. And Herr Schwartzmann took his dismissal as one who cannot dispute his superior.

* * * * *

The room was silent. Harkness stood with downcast eyes that followed with meticulous precision the intricacies of design in the rug on which he stood. A voice was speaking. Not the cool, imperative voice of Mademoiselle Delacoeur, mistress of vast estates, but the voice of Diane—the Diane he had learned to love—and it tore at his emotions until his mind was a whirl of conflicting thoughts.

A tender voice: and there was laughter in it and in the eyes that his own came despondently to meet.

"Such a man, this Walter Harkness!" she was saying. "So hard, so vindictive! Ah, the trouble he will make for me because of my conscienceless agents!"

Harkness threw out his hands in a helpless gesture. "Don't taunt me," he said. "You know you have me tied. You've drawn the charges from all my guns. There is nothing to be done."

Diane Delacoeur drew near. The raillery was gone from her voice, and the hand that she placed on his arm was trembling.

"Nothing?" she inquired. "Then, if friendly rivalry is impossible, would you consider, could there not be arranged—a merger of our interests? I am not thinking now of wealth, of which you will have far more than I: there are so much greater things in life—"

The eyes that clung to his were pleading now. And within them was the light that Walter Harkness at last could understand and define. He took the trembling hand in one of his that was suddenly strong, and with the other he raised a lovely face that no longer dared to meet his look.

"You mean—" he began, and fumbled for words to express an emotion that was beyond words. "Chet said—why, he said—that you needed me—"

Her reply came mingled with a tremulous laugh.

"I have the greatest regard," she whispered, "for Chet's judgement. But—do you—need me?"

Walt Harkness held the soft body close; bent nearer to catch the words. And he answered them with his own lips in an ecstasy of emotion that made nothing of the thrills to be found in that other conquest—of a Dark Moon.

A SCIENTIFIC HELL

Science playing the role of an up-to-date Persephone, visiting the underworld realm of Pluto to wrest from it hidden cosmic secrets, was described recently at a meeting of the American Geographical Society at the Engineering Building by Prof. Harlow Shapley, Harvard astronomical wizard, who told of the ultra-modern scientific version of Ulysses's descent into Hades or Dante's visit to hell.

Prof. Shapley, to whom 10,000,000 light-years are like a day to any ordinary mortal, and whose astronomical investigations have led him to the center of the cosmos, told the scientists present to descend to the bowels of the earth and construct therein "Plutonic Laboratories," where a man could learn many things unknown about beginnings and endings, and where, incidentally he may find a way of utilising the tremendous heat energy stored up in the "scientific hell."

Under the general theme of the "Third Dimension in Geography," Prof. Shapley talked about the past, present and future of the earth-moon system; how in 50,000,000 years our days and months will be forty-seven times as long as they are now; how after that the moon will again approach the earth until it is broken up by tidal disruption into ring fragments circulating around the earth like the ring around Saturn; and of shooting stars coming from far-away solar systems.

"The temperature under the surface of the earth," said Prof. Shapley, "increases one degree Fahrenheit at every seventy-six feet, about seventy degrees per mile. In some places in California we get the temperature of boiling water at a depth of less than a mile. The center of the earth is roughly 4,000 miles below the surface.

"Because of this intense internal heat of the earth it would probably be impossible to maintain permanent laboratories at greater depths than two miles," said the lecturer, "and, in addition, the installation and maintenance of Plutonic laboratories will be a scientific adventure of great difficulty and expense. Yet, if carried on in connection with the work of existing mines and borings it may mark the coming decade as one of the important epochs in man's attempt to understand the earth.

"These Plutonic laboratories, placed at various depths under the surface, fully equipped with modern scientific apparatus, and maintained indefinitely, will contribute to our knowledge in a dozen important fields of geophysic and astronomy."

What Prof. Shapley pointed to as merely a possible by-product of the proposed scientific "descent into Hades" is the commercial possibility of tapping the earth's internal source of heat. There is 31,000,000 times as much natural heat in the earth than in all the coal resources of the world. He stated that Sir Charles Parsons and John L. Hodgson, both noted British engineers, are already engaged in work on this problem.



When Caverns Yawned

By Captain S. P. Meek



[Sidenote: Only Dr. Bird's super-scientific sleuthing stands in the way of Ivan Saranoff's latest attempt at wholesale destruction.]

Bells jangled discordantly. A whistle split the air with a piercing note. A band blared away on the platform. With a growing rumble of sound, the Presidential special slowly gathered headway. The President waved a final farewell to the crowds at the platform and sat down. He chatted cheerily with his companions until the train was clear of Charleston, then rose, and with a word to the others stepped into the car. Operative Carnes of the United States Service slumped back in his chair with a sigh of relief.

"Thank Goodness, that's over," he said. "I was never so glad to get him safely away from a place in my life."

Haggerty of the secret service nodded in agreement. Colonel Holmes, the military aide, looked up inquiringly.

"Why so? Do you think Charleston an especially dangerous place for him to be?"

"Not ordinarily. Charleston is a very patriotic and loyal city, but I have been worried. There have been vague rumors going around. Nothing definite that we could pin down, but enough to make me pretty uneasy."

"I think you've worried needlessly. I have been in constant touch with the Military Intelligence Division and they have reported nothing alarming."

Haggerty chuckled at the look of disgust that spread over Carnes' face. Colonel Holmes bridled visibly.

"Now look here, Carnes," he began.

"Oh, horse-feathers!" interrupted Carnes. "The M.I.D. is all right in its place—Good Lord! What's that?"

* * * * *

The train gave a sudden sickening lurch. Colonel Holmes sprawled in an undignified heap in one corner of the observation platform. Carnes and Haggerty kept their feet by hanging on to the rails. From the interior of the car came cries of alarm. The train righted itself for a moment and then lurched worse than before. There was a scream of brakes as the engineer strove to halt the forward progress. The train swayed and lurched like a ship in a storm. Carnes sprang for the telephone connected with the engine cab and rang excitedly.

"Hello, Bemis," he cried when an answer came: "take off the brakes! Keep moving at full speed, no matter what happens. What? Use your gun on him, man! Keep moving even if the train tips over!"

The train swayed and rocked worse than ever as it began to gather momentum. Carnes looked back along the track and gasped. For three hundred yards behind them, the track was sinking out of sight. The train forged ahead, but it was evident that it also was sinking into the ground. The track behind them suddenly gave. With a roar like a hundred buildings collapsing, it sank out of sight in a cloud of dust. The rear car of the train hung partially over the yawning cavern in the earth for an instant before the laboring engine dragged it to solid ground. The swaying and lurching grew less. For a mile it persisted to a slight degree. With a face the color of a sheet, Carnes made his way into the train. The President met him at the door.

"What's the trouble, Carnes?" he demanded.

"I am not sure, Mr. President. It felt like an earthquake. A great cavern opened in the earth behind us. Our train was almost trapped in it."

"An earthquake! We must stop the train at once and take charge of the situation. An emergency of that sort demands immediate attention."

"I beg you to do nothing of the sort, sir. Your presence would add little to the rescue work and your life is too precious to risk."

"But my duty to the people—"

"Is to keep yourself alive, sir! Mr. President, this may well be an attempt on your life. There are persons who would give anything to do away with you, especially at present. You have not endeared yourself to a certain class in calling for a conference of the powers to curb Russia's anti-religious tactics."

* * * * *

The President hesitated. He knew Carnes well enough to know that he usually spoke from accurate knowledge and with good judgment.

"Mr. President," went on the operative earnestly, "I am responsible to the American people for your safety. I beg you to follow my advice."

"Very well, Carnes," replied the President, "I'll put myself in your hands for the present. What is your program?"

"Your route is well known. Other attempts may be planned since this one failed. Let me have you transferred incognito to another train and hurried through to Washington secretly. I am going to drop off and go back. That earthquake needs to be looked into."

Again the President hesitated.

"My desertion of the stricken area will not be favorably regarded. If I sneak away secretly as though in fear, it will be bad for the public morale."

"We'll let the special go through. No one need know that you have left it."

"Well—I guess you're right. What are you going to do about it?"

"My first move will be to summon Dr. Bird from Washington."

"That's a good move. You'd better have him bring Dr. Lassen with him. Lassen is a great volcano and earthquake specialist, you know."

"I will, sir. If you will get ready to drop of at the next connecting point, I'll send Haggerty and Bemis with you. The rest of the party can remain on the special."

"All right, Carnes, if you insist."

* * * * *

Carnes went forward to the operator of the train's radio set. In half an hour the special came to a stop at a junction point and four men got off. Ten minutes later three of them climbed aboard another train which stopped for them. Carnes, the fourth man, hurried to a telephone. Fifteen minutes later he was talking to Dr. Bird at the latter's private laboratory in the Bureau of Standards.

"An earthquake, Carnes?" exclaimed the doctor as the operative described the happenings. "Wait a few minutes, will you?"

In five minutes he was back on the telephone.

"It was no earthquake, old dear, whatever it may have been. I have examined the records of all three of the Bureau's seismographs. None of them record even a tremor. What are you going to do?"

"Whatever you say, Doctor. I'm out of my depth already."

"Let me think a moment. All right, listen. Go back to Charleston as quickly as you can and get in touch with the commanding officer at Fort Moultrie. I'll have the Secretary of War telephone him and give him orders. Get troops and go to the scene of the catastrophe. Allow no one near it. Proclaim martial law if necessary. Stop all road and rail traffic within a radius of two miles. Arrest anyone trying to pass your guard lines. I'll get a plane from Langley Field and come down on the run. Is that all clear?"

"Perfectly, Doctor. By the way, the President suggested that you bring Dr. Lassen with you."

"Since it wasn't an earthquake, he wouldn't be of much value. However, I'll bring him if I can get hold of him. Now start things moving down there. I'll get some apparatus together and join you in five hours; six at the outside. Have a car waiting for me at the Charleston airport."

* * * * *

Carnes commandeered a passing car and drove back to Charleston. He made a wide sweep to avoid the disturbed area and went direct to Fort Moultrie. Dr. Bird had been good at his word. The troops were assembled in heavy marching order when the detective arrived. A few words to the commanding officer was sufficient to set the trucks loaded with soldiers in motion. Carnes, accompanied by the colonel and his staff, went direct to the scene of the catastrophe.

He found a hole in the ground, a hundred feet wide and a quarter of a mile long, sunk to a depth of fifty feet. He shuddered as he thought of what would have happened had the Presidential train been in the center of the devastated area instead of at the edge. The edges of the hole were ragged and sloping as though the earth had caved in to fill a huge cavern underground.

State and local authorities were already on the ground, striving to hold back sightseers. They were very glad to deliver their responsibility to the representative of the federal government. Carnes added their force to that of the military. In an hour a cordon of guards were stationed about the cavern while every road was picketed two miles away. Fortunately there had been no loss of life and no rescue work was needed. The earth-shaking had been purely a local matter, centered along the line of the railroad track.

There was nothing to do but wait, Carnes thought furiously. He had worked with Dr. Bird long enough to have a fair idea of the scientist's usual lines of investigation.

"The first thing he'll want to do is to explore that hole," he mused. "Probably, that'll mean some excavating. I'd better get a wrecking train with a crane on it and a steam shovel here. A gang of men with picks and shovels might be useful, too."

He hurried to the railroad officials. The sight of his gold badge had the desired result. Telegraph keys began to click and telephones to ring. Carnes was sorely tempted to explore the hole himself, but he resisted the temptation. Dr. Bird was not always pleasant when his colleagues departed from the orders he had given.

* * * * *

The morning passed, and the first part of the afternoon. Two wrecking trains stood with steam up at the edge of the hole. Grouped by the trains were a hundred negroes with shovels and picks. Carnes sat at the edge of the hole and stared down into it. He was roused from his reverie by the sound of a motor.

From the north came an airplane. High over the hole it passed, and then swerved and descended. On the under side of the wings could be seen the insignia of the Air Corps. Carnes jumped to his feet and waved his hat. Lower came the plane until it roared across the cavern less than a hundred feet above the ground. Two figures leaned out and examined the terrain carefully. Carnes waved again. One of the figures waved a hand in reply. The plane rose in the air and straightened out toward Charleston.

"We'll have the doctor here in a few minutes now," said Carnes to the Colonel. "It might be a good plan to send a motorcycle out along the Charleston road to bring him in. We don't want the guards to delay him."

The colonel gave an order and a motorcycle shot off down the road. In half an hour it came sputtering back with a huge Cadillac roaring in its wake. The car drew up and stopped. From it descended two men. The first was a small, wizened figure with heavy glasses. What hair age had left to him was as white as snow. The second figure, which towered over the first, was one to merit attention anywhere.

* * * * *

Dr. Bird was as light on his feet and as quick and graceful as a cat, but there was nothing feline about his appearance. He stood well over six feet in his stockings and tipped the beam close to the two hundred mark. Not one ounce of fat was on his huge frame. So fine was he drawn that unless one looked closely he would never suspect the weight of bone and muscle that his unobtrusive tweed suit covered. Piercing black eyes looked out from under shaggy brows. His face was lean and browned, and it took a second glance to realize the tremendous height and breadth of his forehead. A craggy jutting chin spoke of stubbornness and the relentless following up of a line of action determined on. His head was topped with an unruly shock of black hair which he tossed back with a hand that commanded instant attention.

His hands were the most noteworthy thing about the famous Bureau scientist. Long slender hands, they were, with slim tapering fingers—the hands of an artist and a dreamer. The acid stains that marred them could not hide their slim beauty, yet Carnes knew that those hands had muscles like steel wire and that the doctor boasted a grip that could crush the hand of a professional wrestler. He had seen him tear a deck of playing cards in half and, after doubling, again in half, with as little effort as the ordinary man would use in tearing a bare dozen of the cards. As he climbed out of the car his keen black eyes swept around in a comprehensive glance. Carnes, trained observer that he was, knew that in that one glance every essential detail which it had taken him an hour to place had been accurately noted and stored away in the doctor's mind. He came forward to the detective.

"Has anything happened since you telephoned me?" was his first question.

"Nothing, Doctor. I followed your instructions and also assembled a crew of men with excavating tools."

"You're improving, Carnes. This is Dr. Lassen. This is a little out of your line. Doctor, but you may see something familiar. What does it look like to you?"

"Not like an earthquake, Bird, at all events. Offhand I would say that a huge cavern had been washed in the earth and the ground had caved in."

"It looks that way. If you are right, we should find running water if we dig deep enough. Have you been down in the hole, Carnes?"

"No, Doctor."

"Then that's the first thing to do. You have ropes, of course?"

* * * * *

Carnes called to the waiting gang of negroes and a dozen of these hurried up with ropes. Dr. Bird slung a rope around his body under his arms and was lowered into the hole. The rope slackened as he reached bottom. Carnes lay on his stomach and looked over the edge. Dr. Bird was gingerly picking his way across the ground. He turned and called up.